The invention relates to steering mechanisms for wheeled vehicles and more particularly but not exclusively for four wheel drive vehicles.
In both agricultural and industrial vehicles it is desirable to achieve a small turning circle. It may be difficult to achieve a desired turning circle by means of front wheel steering alone, since the angle through which the front wheels can turn is limited. A reduced turning circle can be achieved by means of four wheel steering.
Four wheel steering, however, has undesirable effects when driving at speed owing to the instability created, but when travelling at speed it is generally the case that only small deviations are required from the straight ahead direction in comparison to a full lock required when, for example, a tractor is negotiating a sharp turn.